Object 140 vs STB-1 (for CW)

Hey guys, I've had this question for some time now.

As the title implies, Object 140 or STB-1? Which would be more suitable for pubs?

In addition, I see many competitive clans saying you must own a 277 and 140 (or their campaign award counterparts such as 279e, 260, 907 etc.). I understand the need for the 277 but why the 140? As far as I know alpha damage is more valuable than raw dpm in the current meta. The K-91 is a beast in terms of raw dpm and gun handling but suffers due to low alpha. I feel as though the same goes for the 140, but clans still value them above the STB-1? I don't understand.

The STB-1 has marginally better dpm and more importantly, better alpha. Pair that with more than double the 140's gun depression and far better power/weight ratios and the STB just seems superior in my eyes.

You could argue that the 140 has better base pen and shell velocity, and that it has far better ground resistances and a higher top speed. However, when it comes it CW it heat that's fired. They have the same heat pen and the STB even has 50m/s better shell velocity. In terms of ground resistance and top speed sure, the 140 is better. However, even with those advantages, I still think the STB is far more flexible for pubs and Clan Wars alike.

With those in mind, I don't understand why the 140 is more preferred in CW over the STB. Any insight would be greatly appreciated. Thanks in advance!